This research article was published in the journal of Alzheimer’s disease and Parkinsonism on August 26th 2013, volume 3, issue 2. Dr.Perea et al. conducted the study at department of neurology, Alzheimer’s Research Disease Center, department of Psychology, Bioengineering program-department of engineering, at University of Kansas School of Medicine, Kansas City, KS, USA.
The big question of this study is to investigate white matter differences to give better understanding of neurodegenerative disease such as Alzheimer’s disease and Parkinson’s disease. It asks specifically whether individuals with Parkinson’s disease dementia will show significant white matter deterioration when ...view middle of the document...
12 individuals have PD, 9 individuals with PDD, 14 individuals with AD, and 13 individuals with non-demented healthy control group.
In this study Dr. Perea et al. compared different brain regions including the cingulum, corticospinal tract, corpus callosum, thalamus, putamen, temporal cortex, and frontal cortex. They compared white matter neural fibers using two markers. First marker used is the fractional anisotropy (FA); which is a scalar that used in diffusion process and has value between zero and one. It records the density of the neural fibers as well as the myelination of the white matter in different brain regions. Second marker used is mean diffusivity (MD); which is used to measure the diffusion of a specific brain region. They compared brain regions among three neurodegenerative diseases: non-demented Parkinson’s disease, Parkinson’s disease dementia, and Alzheimer’s disease using tract based spatial statistics (TBSS). Also, using region of interest analysis (ROI) in the substanstia nigra (SN) to measure dopaminergic neuronal loss (Perea et al. 2013). In addition to using a CDR scale to measure the presence or absence of AD dementia or any impairment in memory over a period of time.
After few tests done on the participants, diffusion weighted images were recorded using MRI scanner, single shot echo-planar imaging sequences with a repetition time TR=1000ms and eco time TE=81MS. The total image acquisition time was twelve minutes (Perea et al. 2013). Then they did an analysis of MD and FA by using tract based spatial statistics (TBSS). Region of interest ROI analysis was used in the substantia nigra area in the four groups. They identified the red nucleus and sub thalamic nucleus region where also the SN is noticeable and they got a slice ventral to that region where the SN is clearly visible. Two markers were recorded from that region and showed as red-green-blue (RGB) principal. They compared these data with the data they got from MD and FA analysis (Perea et al. 2013).
They set their data from this study into three tables. First table set is the comparison of the demographic data which is used to compare between the four different groups which includes: AD, PD, PDD, and the control healthy group. They compared age, sex, education, and disease duration (in years). Second table used to show the fractional anisotropy (FA) between the four groups. Results come from right and left hemispheres. Third table showed TBSS mean diffusivity (MD) for the all the mentioned groups in areas of cingulum, forceps major and minor, corticospinal tract, anterior thalamic radiation, uncinate fasciculus, and superior and inferior fasciculus in both of MD and FA analysis (Perea et al. 2013).
According to the article, the results were:
• They found a very small deficit in projection tracts of forceps major and forceps minor in patients with AD as they compared to PD group.
• White matter deterioration- decreased FA and increased MD- in the SN of PDD...